Geological parameters affecting the marble production in the quarries along the southern flank of the Menderes Massif, in SW Turkey

The Mugla province is one of the major marble producing regions located in the southern flank of the Menderes Massif in SW Turkey. The Menderes Massif is a regionally metamorphosed massif with an old Pan-African core and cover successions from the Permo–Carboniferous to Paleocene. There are four major metamorphic carbonate horizons in the cover successions exploited for the marble production. These horizons are located within the Permo–Carboniferous, Triassic, Upper Cretaceous and Paleocene successions along the southern flank of the Menderes Massif. Here the world wide known marbles with names such as the Mugla Black, the Milas White, Veined, Pearl, Aubergine, Lilac and Lemony, the Mugla White and the Aegean Bordeaux are found.

Detailed geological studies were carried out in selected marble quarries representing the different stratigraphic levels to determine the geological parameters affecting the marble production in the southern flank of the Menderes Massif in SW Turkey. The geological parameters such as bedding, joints, schist interlayers and mica filled joints affecting the block production from the marble beds are considered to be primary features. The presence of dolomite bands and lenses, abnormal sized calcite crystals and emery minerals which affect the slab and the production qualities and appearances are considered to be secondary geological parameters. The primary and secondary geological parameters affecting the marble productions at different stratigraphical levels in SW Turkey, are determined and the practical aspects of these findings are discussed.     

Material properties of the Menderes Massif Marbles from SW Turkey

Marbles are extensively quarried at four different stratigraphical levels from Permo-Carbonifereous to Paleogene in the southern flank of the Menderes Massif in SW Turkey. These marbles differ in color, texture and pattern depending on their stratigraphical levels and are well known in the international trade as the Mugla Black (Permo-Carbonifereous), Mugla White (Cretaceous), Milas Lemon, Lilac, Aubergine, Pearl, Veined and White (Triassic) and Aegean Bordeaux (Paleogene) marbles. The mineralogical, chemical, physical and mechanical properties of the representative marbles samples obtained from the quarries working in four major metamorphic carbonate horizons in the cover successions of the Menderes Massif's southern flank in SW Turkey are determined and the results of over 1700 tests carried out on the selected marble samples are presented. The mean test values of the physical and mechanical tests are in general, found to be above the threshold acceptance values suggested by the American and Turkish Standards for the use of marbles as a building stone and in the same order as the properties of Italian (Carrara) and Greek marbles reported in the literature. Additionally, the mean test values of the marbles have given high correlations with one another and the relations obtained between the index test results determined by simple techniques requiring minimal sample preparation effort and the mean values of the more elaborate engineering tests results are presented as tables and graphs for wider use.     

Prediction of ground vibrations resulting from the blasting operations in an open-pit mine by adaptive neuro-fuzzy inference system

The aim of this study is to predict the peak particle velocity (PPV) values from both presently constructed simple regression model and fuzzy-based model. For this purpose, vibrations induced by bench blasting operations were measured in an open-pit mine operated by the most important magnesite producing company (MAS) in Turkey. After gathering the ordered pairs of distance and PPV values, the site-specific parameters were determined using traditional regression method. Also, an attempt has been made to investigate the applicability of a relatively new soft computing method called as the adaptive neuro-fuzzy inference system (ANFIS) to predict PPV. To achieve this objective, data obtained from the blasting measurements were evaluated by constructing an ANFIS-based prediction model. The distance from the blasting site to the monitoring stations and the charge weight per delay were selected as the input parameters of the constructed model, the output parameter being the PPV. Valid for the site, the PPV prediction capability of the constructed ANFIS-based model has proved to be successful in terms of statistical performance indices such as variance account for (VAF), root mean square error (RMSE), standard error of estimation, and correlation between predicted and measured PPV values. Also, using these statistical performance indices, a prediction performance comparison has been made between the presently constructed ANFIS-based model and the classical regression-based prediction method, which has been widely used in the literature. Although the prediction performance of the regression-based model was high, the comparison has indicated that the proposed ANFIS-based model exhibited better prediction performance than the classical regression-based model.     

A long-term analysis of thundersnow events over the Marmara Region,Turkey

This study aimed to reveal the temporal statistics, formation mechanisms, suitable land/sea surface (LS/SS) and upper-level atmospheric conditions, and predictability of thundersnow (TSSN) events that occurred between 2000 and 2021 in the Marmara Region with atmospheric stability indexes. Aviation reports from 11 airports were analyzed throughout the period, and no TSSN events were found at four airports. A total of 19 TSSN events were identified, and six events were found in 2015, when the sea-effect snow (SES) mechanisms were observed four times. The majority of TSSN events were of very short duration (0–1 h), and no significant trend was observed in terms of intraday distribution. SES mechanism was observed in 17 of the 19 TSSN events, and the dominance of northern flows was detected at all airports and at the sub-inversion upstream levels. In terms of air-sea interaction, suitable temperature differences between the SS and 850/700 hPa (17 °C and 27 °C on average), and the transfer of heat-moisture fluxes from the SS to the upper-atmosphere were possible in almost all TSSN events. In this way, meteorological parameters were sufficient for the formation and strengthening of the convective layer. In addition, the presence of directional wind shear and the observation of inversion layers restricting convective movements at higher levels instead of near the surface ensured that the moisture requirement, lifting mechanism, and unstable atmospheric conditions required for the formation of TS were provided. The CAPE values were very low for winter TSs. Total Total Index and TQ Index produced the most appropriate results for TSSN prediction.

     

Synoptic analysis of dust storm over Arabian Peninsula: a case study on February 28, 2009

Sand and dust storms are causing hazards and problems in aviation as well as the dangers and distresses they cause on living things. The low meteorological visibility, the presence of strong winds with gust, and the transport of dust and sand particles by the wind are dangerous on landing and departure of aircrafts, and even on planes that are parked. The main aim of the study is to examine the meteorological conditions causing the dust storm that took place in the Arabian Peninsula on February 28, 2009, and to determine the source of dust caused dust storm, sand storm, blown sand, and blown dust at the airports. Within the scope of the study, aviation routine weather report (METAR) and aviation selected special weather report (SPECI) reports have been assessed at many airports over Arabian Peninsula (AP), the northern part of the AP and North Africa. As model outputs; NCEP–DOE Reanalysis 2 data, BSC–DREAM8B, and HYSPLIT model were used. In the satellite images; METEOSAT MSG dust RGB images, MODIS, and Kalpana-1 data were used. According to obtained results, dust storms were detected in Bahrain, Kuwait, Saudi Arabia, and United Arab Emirates (UAE). At Al-Ahsa Airport in Saudi Arabia, the lowest visibility measured on February 28, 2009, dropping to 200 m, which was dominated by blowing sand. The source region of the dust observed at Dubai Airport in UAE is the eastern regions of the Rub’al Khali Desert located between Saudi Arabia, Oman, and UAE.     

The importance of fractional crystallization and magma mixing in controlling chemical differentiation at Süphan stratovolcano,eastern Anatolia,Turkey

Süphan is a 4,050 m high Pleistocene-age stratovolcano in eastern Anatolia, Turkey, with eruptive products consisting of transitional calc-alkaline to mildly alkaline basalts through trachyandesites and trachytes to rhyolites. We investigate the relative contributions of fractional crystallization and magma mixing to compositional diversity at Süphan using a combination of petrology, geothermometry, and melt inclusion analysis. Although major element chemistry shows near-continuous variation from basalt to rhyolite, mineral chemistry and textures indicate that magma mixing played an important role. Intermediate magmas show a wide range of pyroxene, olivine, and plagioclase compositions that are intermediate between those of basalts and rhyolites. Mineral thermometry of the same rocks yields a range of temperatures bracketed by rhyolite (~750°C) and basalt (~1,100°C). The linear chemical trends shown for most major and trace elements are attributed to mixing processes, rather than to liquid lines of descent from a basaltic parent. In contrast, glassy melt inclusions, hosted by a wide range of phenocryst types, display curved trends for most major elements, suggestive of fractional crystallization. Comparison of these trends to experimental data from basalts and trachyandesites of similar composition to those at Süphan indicates that melt inclusions approximate true liquid lines of descent from a common hydrous parent at pressures of ~500 MPa. Thus, the erupted magmas are cogenetic, but were generated at depths below the shallow, pre-eruptive magma storage region. We infer that chemical differentiation of a mantle-derived basalt occurred in the mid- to lower crust beneath Süphan. A variety of more and less evolved melts with ≥55 wt% SiO₂ then ascended to shallow level where they interacted. The presence of glomerocrysts in many lavas suggests that cogenetic plutonic rocks were implicated in the interaction process. Blending of diverse, but cogenetic, minerals, and melts served to obscure the true liquid lines of descent in bulk rocks. The fact that chemical variation in melt inclusions preserves deep-seated chemical differentiation indicates that inclusions were trapped in phenocrysts prior to shallow-level blending. Groundmass glasses evolved after mixing and display trends that are distinct from those of melt inclusions.